This invention relates to air system analyzing means and is particularly directed to a method and apparatus for analyzing the performance of low volume air systems.
As is well known, the fish and plants in an aquarium obtain the air necessary for their survival from that dissolved in the water and the usual practice is to provide a low volume pump to deliver the required air through various devices, such as air stone feeders. In addition, air is used to operate a wide variety of aquarium accessories such as filters and decorative displays.
Low volume pumps, such as those used to supply air to the water in aquariums, typically consist of one or more active pump elements arranged in various combinations in a common housing with one or more external supply nozzles. Each of the active elements of the pump functions in a fashion similar to a quasi-reverse two-cycle internal combustion engine; the driving agent or "piston" being a flexible cup-shaped diaphragm which is vibrated atop a two compartment "cylinder". The top of the diaphragm is moved up and down by the action of a cantilevered armature, one end of which is hinged and the other fitted with a permanent magnet which oscillates in an electromagnetic field of reversing polarity induced by standard 60 Hz alternating current. As the diaphragm moves up, the pressure is lowered in the upper compartment, causing the first of two flexible flapper valves to open admitting ambient air to that compartment, while at the same time causing a second flapper valve to close off the lower compartment. This action comprises the "intake" stroke. As the diaphragm moves down, it causes the first valve to close under increased pressure and the second valve to open thereby joining the two compartments. This is the "power" stroke. The lower compartment connects directly to the external supply nozzle or nozzles. Ambient air generally enters the pump housing through a porous filter.
The output characteristics of the single element pump, as defined above, differ from those of a multi-element pump due to dynamic interactions in the latter due to resulting phase differences. Thus, experimental plots of these characteristics yield two distinct "families" of curves for single versus multi-element pumps.
Some air pumps incorporate a variable feature whereby the voltage applied to the electromagnets is changed to cause proportional changes in the armature amplitude, hence resulting in the piston stroke providing a variable air delivery rate. This may be done using a knob-driven rheostat. The maximum output of these pumps is approximately 500 standard cubic inches per minute at 3 PSI. However, this is extreme and is only possible by ganging the outputs of two or more of the pumping elements described above. The air pump supplies air through suitable tubing to a delivery device, such as an air stone feeder, located within the aquarium which discharges the air to bubble through the water.
During use, the performance of the air system may be altered by clogging of the filter or diaphragm of the pump by dirt, smoke, grease or the like carried in the air. Moreover, algae or sediment contained in the water may tend to clog the air stone feeder. In addition, mechanical failure may affect one or more elements of the air system and numerous other things may occur to diminish or block the delivery of air o the water. Obviously, assuring that the pump and air system are functioning properly and that the air supply is adequate is vital to the welfare of the aquarium ecosystem. Unfortunately, however, no apparatus has been available heretofore for providing such assurance. A search in the U. S. Patent Office has located the following:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 2,826,067 R. H. Braunlich Mar. 11, 1958 3,117,446 W. F. Green Jan 14, 1964 3,196,673 T. A. Carson July 27, 1965 3,289,464 E. L. Byrkett et al Dec. 6, 1966 3,446,066 G. Israelson May 27, 1969 3,757,577 J. W. Bozek Sept. 11, 1973 3,842,671 W. G. Frizelle Oct. 22, 1974 3,985,029 W. F. Green Oct. 12, 1976 4,257,279 J. Marx Mar. 24, 1981 4,322,972 A. L. Karjala Apr. 6, 1982 4,491,023 S. Graef Jan. 1, 1985 ______________________________________
Each of these references discloses flow metering apparatus. However, none of the prior art suggest means for analyzing the performance and mechanical conditions of a pump.